Content uploaded by Eric W. Davis
Author content
All content in this area was uploaded by Eric W. Davis
Content may be subject to copyright.
A preview of the PDF is not available
Space testing of electromagnetically sensitive materials for breakthrough propulsion physics
Abstract
Recently it has been experimentally demonstrated that non-local (instantaneous) communication between two beams of light (spin direction) can randomly occur. The effect is described as a consequence of the physics of quantum mechanics. Other research has experimentally demonstrated that the zero point radiation/fields (ZPF), which pervade space-time, can effectively be shielded so as to force two parallel plates together (Casimir effect). The NASA Marshall Space Flight Center is investigating the possibility that a spinning superconductor can cause a reduction in the weight of nearby objects. Recent ultrahigh-intensity, peta/eta-watt tabletop lasers have achieved extreme electric and magnetic fields, pressure, temperature and space-time curvature that can only be found close to a black hole horizon. Based on these research and experimental efforts, some examples of space experiment and materials/technology testing approaches have been examined to determine the feasibility and potential benefits of using the International Space Station (ISS) to address breakthrough propulsion physics and technology challenges. The ISS's microgravity environment, combined with the access to an extreme vacuum and plasma environment, offers some unique advantages for the testing of various electromagnetically "sensitive" materials, and associated physical interactions. The use of this space laboratory could enable much more rapid progress in the identification and optimization of anomalous and highly nonlinear effects. A modular Breakthrough Propulsion Physics testbed could be developed using one or two mid-deck locker equivalent volumes in a pressurized Express Rack, which would enable the operation or testing of various experiments and devices as part of a long duration, breakthrough physics and technology testing program. Similarly, an Express Pallet adapter site could be used as a breakthrough propulsion physics testbed for those experiments or technology demonstrations which require direct access to the space environment and larger operating volumes. Breakthrough propulsion physics experiments could also be integrated into (or use extra space in or on) micro-/nano- technology (MNT) experiments which are already under development. The International Space Station's research capabilities provide important opportunities for achieving early breakthroughs in physics understanding, and the associated materials/technology interactions, needed to accelerate advances in space vehicle/platform maneuvering and transport.
ResearchGate has not been able to resolve any citations for this publication.
Although mathematically self-consistent, Carlip’s approach to the reanalysis of Sakharov gravity is flawed by the neglect of important physical constraints associated with the interaction, and leads to an incorrect 1/R4 spatial dependence for the force. When appropriate physical cutoffs are incorporated into the modeling, however, inverse-square-law Newtonian gravity emerges as originally derived.
Space flight by means of wormholes is described whereby the traditional rocket propulsion approach can be abandoned in favor of a new paradigm involving the manipulation of spacetime. Maccone (1995) extended Levi-Civita’s 1917 magnetic gravity solution to the Morris and Thorne (1988) wormhole solution and claimed that static homogeneous magnetic/electric fields can create spacetime curvature manifesting itself as a traversable wormhole. Furthermore, Maccone showed that the speed of light through this curvature region is slowed by the magnetic (or electric) induced gravitational field there. Maccone’s analysis immediately suggests a way to perform laboratory experiments whereby one could apply a powerful static homogeneous magnetic field in a vacuum, thereby creating spacetime curvature, and measure the speed of a light beam through it. Magnetic fields employed in this scenario must achieve magnitudes >1010 Tesla in order for measurable effects to appear. Current magnetic induction technology is limited to static fields of ∼several×103 Tesla. However, destructive chemical (implosive/explosive) magnetic field generation technology has reached peak rate-of-rise field strengths of ∼109 Tesla/s. It is proposed that this technology be exploited to take advantage of the high rate-of-rise field strengths to create and measure spacetime curvature in the lab.
Quantum theory predicts, and experiments verify, that empty space (the vacuum) contains an enormous residual background energy known as zero-point energy (ZPE). Originally thought to be of significance only for such esoteric concerns as small perturbations to atomic emission processes, it is now known to play a role in large-scale phenomena of interest to technologists as well, such as the inhibition of spontaneous emission, the generation of short-range attractive forces (e.g., the Casimir force), and the possibility of accounting for sonoluminescence phenomena. ZPE topics of interest for spaceflight applications range from fundamental issues (where does inertia come from, can it be controlled?), through laboratory attempts to extract useful energy from vacuum fluctuations (can the ZPE be ª minedº for practical use?), to scientifically grounded extrapolations concerning ª engi- neering the vacuumº (is ª warp-driveº space propulsion a scientific possibili- ty?). Recent advances in research into the physics of the underlying ZPE indi- cate the possibility of potential application in all these areas of interest.
Over the past ten years, laser intensities have increased by more than four orders of magnitude to reach enormous intensities of 10 20 W / cm 2 . The field strength at these intensities is on the order of a teravolt per centimeter, or a hundred times the Coulombic field binding the ground state electron in the hydrogen atom. The electrons driven by such a field are relativistic, with an oscillatory energy of 10 MeV. At these intensities, the light pressure, P = I/c, is extreme, on the order of giga‐ to terabars. The laser interacting with matter—solid, gas, plasma—generates high‐order harmonics of the incident beam up to the 3 nm wavelength range, energetic ions or electrons with mega‐electron‐volt energies (figure 1), gigagauss magnetic fields and violent accelerations of 10 21 g (g is Earth's gravity). Finally, the interaction of an ultraintense beam with superrelativistic particles can produce fields approaching the critical field in which an electron gains in one Compton wavelength an energy equal to twice its rest mass. Under these conditions, one observes nonlinear quantum electrody‐namical effects. In many ways, this physical environment of extreme electric fields,magnetic fields, pressure, temperature and acceleration can be found only in stellar interiors or close to the horizon of a black hole. It is fascinating to think that an astrophysical environment governed by hydrodynamics, radiation transport and gravitational interaction can be re‐created in university laboratories for extremely short times, switching the role of the scientist from voyeur to actor. By stretching, amplifying and then compressing laser pulses, one can reach petawatt powers, gigagauss magnetic fields, terabar light pressures and 1022 m/s2 electron accelerations.
If gravity from the Sun propagated outward at the speed of light, the transmission delay would progressively increase the angular momentum of bodies orbiting the Sun at so great a rate that orbital radii would double in about 1000 revolutions. Direct measurements of the directions of bodies and their accelerations show that, while light of any wavelength undergoes aberration as an immediate consequence of its finite speed, gravity has no such aberration or propagation delay at a detectable level. Dynamical studies of binary pulsars show that not only the position and velocity of a source of gravity are anticipated without light-time delay, but accelerations of the source are anticipated as well. Indeed, Newton's universal law of gravity, to which general relativity is supposed to reduce in the low-velocity, weak-field limit, requires infinite propagation speed for gravity. These paradoxes are supposed to be explained by general relativity's curved spacetime interpretation of gravity. Yet that interpretation leads to new, equally unresolvable paradoxes, especially acute in the case of binary black holes. Moreover, that interpretation is in conflict with results from neutron interferometer experiments. One resolution of the paradoxes is to interpret the experiments literally, and from them deduce that the speed of propagation of gravitational force is at least 2 x 10(10) c. Although this is inconsistent with the Einstein interpretation of special relativity, it is consistent with the Lorentzian variant of that theory. This subtle alteration in our thinking about what is allowed under the laws of physics has several beneficial consequences. Examples are the locality dilemma of quantum mechanics and the question of the existence of singularities in nature ("black holes").
Rapid interstellar travel by means of spacetime wormholes is described in a way that is useful for teaching elementary general relativity. The description touches base with Carl Sagan's novel Contact, which, unlike most science fiction novels, treats such travel in a manner that accords with the best 1986 knowledge of the laws of physics. Many objections are given against the use of black holes or Schwarzschild wormholes for rapid interstellar travel. A new class of solutions of the Einstein field equations is presented, which describe wormholes that, in principle, could be traversed by human beings. It is essential in these solutions that the wormhole possess a throat at which there is no horizon; and this property, together with the Einstein field equations, places an extreme constraint on the material that generates the wormhole's spacetime curvature: In the wormhole's throat that material must possess a radial tension tauâ with the enormous magnitude tauâapprox. (pressure at the center of the most massive of neutron stars) x (20 km)²/(circumference of throat)². Moreover, this tension must exceed the material's density of mass-energy, rhoâc². No known material has this tauâ>rhoâc² property, and such material would violate all the ''energy conditions'' that underlie some deeply cherished theorems in general relativity. However, it is not possible today to rule out firmly the existence of such material; and quantum field theory gives tantalizing hints that such material might, in fact, be possible.
The vacuum stress between closely spaced conducting surfaces, due to the modification of the zero-point fluctuations of the electromagnetic field,has been conclusively demonstrated. The measurement employed an electromechanical system based on a torsion pendulum. Agreement with theory at the level of 5% is obtained. {copyright} {ital 1996} {ital The American Physical Society}
This paper reviews the development of ultrahigh-intensity laser technology from the early 1960`s to the present, explaining the obstacles to each increase in intensity and the technical means used to overcome them. These included the shortening of pulses, mode locking, and chirped pulse amplification (CPA). The particular technical advances that make CPA possible included the invention of matched pulse stretchers and compressors and the development of ultrabroadband gain media. The paper then discusses the generation of ultrashort pulses and their characteristics. It then moves on to the Petawatt laser, which incorporates the CPA technology. It then addresses the question of whether it is possible to forecast the ultimate peak power that can be achieved by a laser system of a given size. Applications of ultrahigh-intensity lasers in different physical regimes are discussed.
Any pair of conducting plates at close distances (< μm) experience an attractive Casimir force that is due to the electromagnetic zero-point fluctuations of the vacuum. A "vacuum-fluctuation battery" can be constructed by using the Casimir force to do work on a stack of charged conducting plates. By applying a charge of the same polarity to each conducting plate, a repulsive electrostatic force will be produced that opposes the Casimir force. If the applied electrostatic force is adjusted to be always slightly less than the Casimir force, the plates will move toward each other and the Casimir force will add energy to the electric field between the plates. The battery can be recharged by making the electrical forces slightly stronger than the Casimir force to reexpand the foliated conductor.